Poland

Kuyavia (Polish: Kujawy) is a historical and ethnographical region in the center of Poland in the Greater Poland Lakes area. Kuyavia is situated in the basin in the middle of Vistula River and upper Noteć River, with its capital in Włocławek.
The etymology of the name Kuyavia was seen differently in history. The most probable explanation has been put forward by professor Stanisław Rospond who thinks the name Kuyavia derives from the words kui, kuiati, meaning: gale and also flat, dune land which was at the risk of this gale. Though, the etymology of the name Kuyavia is connected with the physiography of the land.
For the first time, the name Kuyavia appeared in written sources in 1136 in the Bull of Gniezno (Polish: Bulla Gniźnieńska, Latin: Ex commisso nobis. The Bull of Gniezno was issued by the Pope Innocent II.
Later, the name of the land was mentioned in many documents from medieval times. It is also mentioned in the chronicles of Wincenty Kadłubek.
The episcopal see of Kuyavia was Kruszwica, and later Włocławek (after the episcopal see in the early 12th century). The capital of this Duchy, and later (from 14th century until the year 1772) the residences of the governor was Inowrocław, Brzesć Kujawski, and Radziejów as a residence of the shared Regional Council of the Kuyavia provinces. Now, the biggest centres of Kuyavia is Bydgoszcz, Włocławek and Inowrocław. Also the southern part of Toruń (Podgórz) lies in the historical region of Kuyavia. This region is divides into White Kuyavia (west) with the capital in Inowrocław and Black Kuyavia (east) with the capital in Włocławek. The latin equivalent for Inowrocław delineates it as New Włocławek. The capital of Kuyavia is Włocławek.
Kuyavia lowland has an average high of 100-130 meters above sea level, is post-glacial landscape, slightly undulating, in some places there are moraine hills elevations and sandy gravel embankments. In deep dykes and depressions is about 600 lakes with surface higher than 1 kilometre, under ice formation there are layers of rock-salt and potassium, in the layers from the Tertiary Period there are layers of lignite and ceramic clay.